Prevalence and Impact of Under- or Misdiagnosed ADHD in Adults Referred for the Treatment of Mood and Anxiety Disorders

The comorbidity between Attention-Deficit Hyperactivity Disorder (ADHD) and psychiatric disorders has been well documented. Still, many clinicians fail to screen adult patients for ADHD, despite evidence that adolescents with a history of ADHD are significantly more likely to develop anxiety and depression by adulthood. The aim of this study was to determine the percentage of patients with under- or misdiagnosed ADHD referred for the treatment of mood and anxiety disorders.

Data was collected from consecutive referrals (N = 160) to a tertiary-care mood and anxiety clinic. Diagnosis was established by the Mini International Neuropsychiatric Interview Plus (MINI) 6.0.0, ADHD module, and semi-structured interview. Chi-square analyses were performed to assess group differences and predictive factors.

Adult ADHD was present in 36.9% of referrals, 29.4% had comorbid anxiety, and 20.6% had comorbid depression. Misdiagnosed ADHD occurred in 28.7% of referrals χ²(4) = 44.8, p < .001, Φ = .529. In treatment-resistant referrals 38.2% of GAD and 34% of depression had comorbid ADHD, with 4.4% and 100% undetected respectively. The main predictive factor of misdiagnosis was number of referral diagnosis χ²(9) = 39.5, p < .001, Φ = .597.

ADHD is a common and treatable disorder that it is often under- or misdiagnosed in adults presenting with mood and anxiety disorders. This study signifies the importance of early and accurate diagnosis of ADHD in adults presenting with mood and anxiety disorders. Increased awareness and use of screening tools may allow for selection of targeted treatment and improved clinical outcomes.